1. Technical Field of the Invention
The invention relates to optical display devices, and to methods for making the same.
2. Background of the Related Art
Liquid crystal display (LCD) devices are one example of well-known display devices that are useful in a number of applications where light weight, low power and a flat panel display are desired. Typically, these devices comprise a pair of sheet-like, glass substrate elements or xe2x80x9chalf-cellsxe2x80x9d overlying one another with liquid crystal material confined between the glass substrates. The substrates are sealed at their periphery with a sealant to form the cell or device. Transparent electrodes are generally applied to the interior surface of the substrates to allow the application of an electric field at various points on the substrates thereby forming addressable pixel areas on the display.
Various types of liquid crystal materials are known in the art and are useful in devices referred to as twisted nematic (TN), super twisted nematic (STN), cholesteric, and ferroelectric display devices.
Other types of display device are electroluminescent displays, such as organic light emitting devices (OLEDs) and polymer light emitting device (PLEDs).
It is desirable to be able to manufacture large area displays of relatively light weight for use in portable devices such as computers, electronic books, personal digital assistants, and the like. Certain organic, polymeric substrates are much lighter than glass while being transparent and are therefore preferred for use over glass in large area, lightweight displays. However, one problem with polymeric substrate displays is the difficulty of properly aligning such substrates, especially if both films are produced using roll-to-roll formation processes. In addition, polymeric substrates often require organic or inorganic coatings with high barrier properties, to prevent ingress of moisture, oxygen, and/or other contaminants into the substrates.
A display includes a front panel and a back panel with a light control material in between. One of the panels includes a rigid substrate, for example made of glass or rigid plastic. The other of the panels includes a flexible substrate, for example made of a flexible plastic film. A method of making the panel includes separately fabricating the panels, and then combining them together. The separate fabrication may include performing various roll-to-roll fabrication operations on the panel with the flexible substrate while the flexible substrate is still part of a web of material. The panels with the rigid substrate may be separately fabricated, then combined with the other panel on the web through a pick and place operation that accurately locates the panel relative to the one another. The combined panels may be then separated from the web to form the display. The display may be any of a variety of displays, such as liquid crystal displays (LCDs), and electroluminescent displays, such as polymer light emitting devices (PLEDs) and organic light emitting devices (OLEDs).
According to an aspect of the invention, a method of producing a display includes: forming a first panel having a rigid substrate; forming a second panel having a flexible substrate, wherein the forming includes roll forming the second panel on a web of the flexible substrate material; placing the first panel on the second panel; joining the first panel and the second panel; and separating the joined panels from the web.
To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.